Mobility management is an important task in a wireless mobile communications system. Usually, the mobility management may include mobile network switching, cell reselection, and the like for user equipment (UE).
In a Long Term Evolution (LTE)/LTE-advanced (LTE-A) system of the 3rd Generation Partnership Project (3GPP), the UE may be in an idle state or a connected state. The UE in the idle state is not connected to a base station, cannot send data, and performs cell reselection in a moving process. If the UE in this state needs to send data, the UE needs to switch to the connected state first. The UE in the idle state may enter the connected state after obtaining a connection context and a dedicated identifier of the UE in a cell in a radio resource control (RRC) connection establishment process. The UE in the connected state is connected to the base station, and can send data, and handover is performed when the UE moves. The UE in the connected state may enter the idle state after an RRC connection release process.
A typical procedure of the handover of the UE in the connected state may include the following steps: A source base station, that is, a current serving base station of the UE, configures a measurement parameter for the UE; the UE performs measurement and reports a measurement result to the source base station; the source base station sends a handover request to a target base station, and sends a handover command to the UE after confirmation by the target base station; and the UE accesses the target base station, obtains uplink synchronization, sends a handover completion message, and the like.
In future network evolution, there are more and more network deployment forms, such as a heterogeneous network (Hetnet), coordinated multiple points (CoMP) transmission, small cell networking, small cell dense networking, and the like. These network deployment forms pose a new challenge to UE mobility management. If the existing handover procedure is still used, the UE needs to continuously perform measurement and reporting. This requires a large amount of handover signaling overhead, and wastes radio resources.